Variable-camber rib for aeroplane-wings



H. F. PARKER.

VARIABLE CAMBER RIB FOR AEROPLANE wmas.

I APPLICATION FILED JULY 11,1919- I 1,341,758. Patented June 1, 1920.

- UNIT srr s HUMPHREY FRANCTS PARKER, OF DUNEDIN, NEW ZEALAND.

VIABLE-CAMBER RIB FOR AEROPLANE-WINGS.

To all whom it may concern.-

Be it known that I, HUMPHREY F. PAR- KER, a sub'ect of the King of England, re-' siding at unedin, in the Provincial District of Otago and Dominion of New Zealand, have invented certain new and useful Improvements in Variable-Camber Ribs for Aeroplane-Wings; and I do hereby (is-- ings, and to characters of reference marked thereon, which form a part of this specification.

The present invention relates, generally, to improvements in aeroplanes; and the 1nvention has reference, more particularly, to a means whereby the speed range of aeroplanes is increased, so that in aeroplanes designed to have the same maximum speed, lower speeds are obtained for taking off and alighting than is possible with machines heretofore constructed, and in aeroplanes designed to have the same minimum speed higher maximum speeds are obtainable than heretofore.

The invention has for its principal object to provide a novel construction of supporting rib, adapted to carry the lifting surface of an aeroplane, or any desired portion of said lifting surface, which automatically operates to vary the camber of said lifting surface or desired portion thereof, to the end that the same is capable of changing its shape and itsangle of incidence during fli ht.

bther objects of the present invention,

not at this time more particularly enumerated will be clearly understood from the following detailed description of the same.

Vith the various objects of my present invention in view, the same consists, primaril y, in the novel construction of flexible supporting rib structure for aeroplane wings hereinafter set forth; and the invention consists, furthermore, in the various arrangements, and combinations of the sevcral devices and parts, as well as in the details of the construction of said devices and.

parts, all of which will be more fully described in the following specification, and then finally embodied in the claims which are appended thereto.

Specification of Letters Patent.

Patented June i, 1920.

A Application filed July 17, 1919. Serial No. 311,432.

The invention is clearly illustrated in the accompanying drawings, in which Figure l is a side elevation of my, novel construction of supporting rib illustrating its contour when it assumes 'a streamline shape for high speeds.

Fig. 2 is a side-elevation of my'novel construction of supporting rib illustrating its contour when it assumes its maximum lift- .ing shape for landing and taking off.

Fig. 3 is a partial detail longitudinal section of my supporting rib, drawn on an enlarged scale.

F ig.4 is a transverse section taken on line 4-4 in said Fig. 3., the same being drawn on a further enlarged scale.

Similar characters of reference are employed in all of the hereinabove described views, to indicate corresponding parts.

Referring now to said drawings, the reference character. 1 indicates the front spar of an aeroplane wing, and the referencecharacter 2 indicates the rear spar of the I same, with which spars the rib structures are arranged so as to be properly carried thereby.

The rib structure comprises, essentially, a flexible body-portion A extending between the front spar 1 and rear spar 2, and a rigid tail-portion B extending rearwardly from said rear-spar, but being slidably arranged for movement over the same. Said'rigid tail-portion B is connected with said flexible body-portion A in a peculiar and characteristic manner, to besubsequently desecured by their forward ends to said front spar 1. Said respective longitudinal members or strips 3 and 4 are preferably made of steel having a shallow channelshape in cross-section, with their channel faces turned inward, and the same are designed to flex when a change of shape of the rib structure is effected.

Pivotally interconnected between said longitudinal members or strips 3 and 4 are a Said respective longitudinal members or strips 3 and 4 are anchored or series of longitudinally spaced compression links 5. Said compression links may be made of any suitable shape and of any suitable material, but, preferably, are of a rigid channel steel construction provided with.

pairs of perforate ears or lugs 6 at their respective ends. Said longitudinal members otal connection of said compression links '5 therewith, with perforate ears 7 between which are received and registered the ears or lugs 6 of said compression links, so that transverse pivoting pins 8 supported by said ears 7 may pass through the ears or lugs 6 to establish the desired pivotal connection between the lon itudinal members or strips, 3 and 4 and sai' compression links 5. The function of the compression links is to maintain the longitudinal members or strips 3 and 4 in proper relative spaced re lation one to the other at all times and to complete the frame.

- Interconnected between the upper and lower longitudinal members or strips 3 and 4, preferably by securing their ends upon the pivoting pms 8 between the ears or lugs 6 of the compression links 5, are a series of diagonal flexible steel bracing straps 9 adapted to arrest deformation of the flexi le body-portion A of the rib beyond the desired change of shape effecting its lifting form, and a second series of diagonal flexible steel" bracing straps 10 adapted to arrest deformation of the flexible body-portion A of the rib beyond the normal return from its lifting form to its high speed or stream line shape. When the aeroplane wing or lifting surfaces, as supported by novel construction of ribs, is subjected to an overload, such 6. g. as is likely to occur in flattening out after a steep dive, the compression links 5 together with the diagonal bracing straps 9 provide a truss-like structure, in which a limited amount of rotary motion is permitted between the compression links 5 and the longitudinal members or strips 3 and 4 sufficient to permit the rib to effect desired change of shape; in which truss-like structure the diagonal bracing straps 9 (which when the rib is in its streamline shape are slackened off or bowed) are tautened when the desired change to lifting shape is accomplished so as to limit any I further flexing of the longitudinal members or strips 3 and 4. The diagonal bracing tautened when the change to streamline shape is accomplished so as to limit any further flexing of the longitudinal members or strips 3 and 4 beyond that shape, especially' when the wing or lifting surface isv ber or strip 11 and a lower rigid longitudinal member or'strip 12, the-same converging relatively toward their rear extremities or trailing ends, and being secured together in rigid relation one to the other by means of intermediate truss-bars 13 secured to said respective members or strips 11 and12 either as an integral part thereof, or in any other suitable manner.v Preferably said' tail-portion is made of a suitable metal, an'd either in a cast or stamped form of construction. The forward extremity of the upper member or strip 11 is securely anchored to the rearward extremity of the upper flexible member or strip 3, by means of rivets 14, or in any other suitable manner. The forward extremity of the lower member or strip 12 is associated with the rearward extremity "of the lower flexible member or strip 4 for slidable longitudinal movement relative to the latter; to this end the said forward extremity of the lower member or strip 12 is received in and rides inthe channel of said lower flexible member or strip 4, the flanges ward end with a space 17 t rough which the rear spar 2 extends. The horizontal dimen-' sions of said space 17 is greater than the width of the spar 2 by the distance of forward travel of tail-portion B as determined by the amount of upward deflection permitted to the flexible body-portion A between the spars 1 and 2, when said flexible body-portion changes from streamline to lifting shape.

The flexible members or strips 3 and '4' may be designed to have sufficient rigidity 1 to enable them to returnto and maintain their'streamline shape under high speed flying conditions, and yet of sufficient flexibility to, enable them to flex to their lifting shape under normal flying load; preferably, however, the flexible members or strips 3 and 4 are made slightly less rigid, or in other words slightly more flexible, than would be necessary if acting alone, and then supplementing the action thereof by aid of a helical compression spring 18 placed between the rear spar 2 and the adjacent vertical truss-member of the tail-portion B immediately in the rear of said spar 2.

Connected with the forward ,side of the front spar 1 is a light nose-piece19, preferably made of wood and of convex contour on its outward or forward surface, the same running coincident with the entire outward spread of the aeroplane wing to give a fair shape to the leading edge of the latter.

It will be understood that in the construction of the wings or lifting surfaces of aeroplanes,,embodying the novel rib structure above described, that said ribs are'mounted in connection with the front and rear'spars in desired spaced relation one to the other throughout the extent or spread of the wing or lifting surface, or throughout so much of said extent or Spread as it is desired to render automatically variable as to its camber. The fabric of the. wing is spread over the supporting structure provided by the spars and interconnecting ribs.

The operation of the ribs to vary the camber of the wing'or lifting surface, or of any desired portion of the'latter, is automatically accomplished by the functioning of my novel rib structure. 7 The desired changes of shape of the wing. or lifting surface being brought about by the changes of pressure upon and distribution of pressure over. the wing surface. When the pilot of the aeroplane pulls the control stick back, the attitude of the aeroplane is altered, and the variable portions of the wings thereof instead oflying along the direction of the air flow,

are inclined to said flow. The air pressure thus brought into play acts against the variable portions of the wing and causes them to change to the desired shape. The air pressure on the portion of the plane between the front spar 1 and. rear spar 2 being greater than the pressure on the portion be tween the rear spar 2 and the trailing edge, the portion between the spars, to wit, that supported by the flexible body-portions of the ribs'is compelled to move or bow upwardly, and the portion between the rear spar and the trailing edge, to wit, that supported by the rigid tail-portions of the ribs is compelled to move or swing downward,

.thus altering the shape of the plane or variable portion thereof to a maximum lifting shape. 'When such changeof shape occurs the upper and lower flexible members 3 and 4 of each rib flex or bow upwardly, at the same time drawing forward upon the rear spar 2 the i 'id tail-portions of each rib, whereby the latter are inclined or swing downwardly from the rearspar, and at the same time the supplementary auxiliary compression springs 18 are placed under compressio'n. \Vlien the pilot wishes to fly the aeroplane at maximum speed again, and

alters the elevator accordingly to bring the attitude of the aeroplane back to normal, the planes or variable portions thereof are again brought to lie along the direction of air flow, so that the spring action of the flexible members 3 and 4, supplemented by the stored compression of the springs 18, quickly causes thevariable ribs to return to or reassume a streamline shape, and consequently thereby position the lifting surfaces of the planes at a lesser angle of incidence.

.tion of each plane is of fixed My novel invention may be used in that type of aeroplane having two or more planes, one of which is of ordinary construction and the remainder of variable construction employing my novel rib structure; or the invention may be used in an aeroplane having one or more planes in which a poror ordinary construction while the remainder is of variable construction employing my novel rib structure. In aeroplanes constructed in either manner it is the function of the variable portion of the plane areas to change its shape from a streamline contour to a.

maximum-lifting shape (to wit, giving the upper surface of the wing greater convexity and the'lower surface a marked concavity) presented at a greater angle of incidence so as to render the same capable of assisting in supporting the weight of the machine at low speeds, and in landing and taking off. When the aeroplane is flying at high speed the variable portion of the plane areas assume a streamline shape (to wit, giving both the upper and lower surfaces of the wing a comparatively equal and small degree of convexity) presented at a lesser angle of incidence, so as to lie. along the direction of air flow, thus ofii'ering less resistance or drag, al-

though not contributing materially to the lift of the machine. In such aeroplanes the fixed'plane surfacecarries the whole weight of the machine'at high speeds, and a portion only of the weight when landing, while the variable plane surface assists in carrying the weight of the machine when landing or flying at lower speed, but to carry none of the weight when flying at high speed.

' While in the claims I have used. the term aeroplane wings I do not thereby intend to confine myself to the use of my novel ribs in the lifting surfaces of heavier than air machines, but intend that the same'may be applied in use to any lifting surface of wing type whether employed in heavier than air machines Or in-lighter than airmachines.

I claim Y 1. A variable camber rib for aeroplane wings having, front and'rear spars, comprising a flexible body portion having its forward end fixed to said front spar, a rigid tail-portion having a slidable and oscillatable relation to saidrear spar, said rigid tail-portion being connected with said flexible body portion whereby flexing of the latter produces an oscillationof the rigidtailportion.

2. A variable camber rib for aeroplane wings-having front and rear spars, comprising a flexible body portion having its forward end fixed to said front spar, a rigid tail-portion having a slidable and oscillatthe latter produces a limited forward sliding movement upon and a downward swing.

from said rear spar of said tail-portion.

3. A variable camber rib for aeroplane wings having front and rear spars, comprising a flexible body-portion between said front and rear spars, a rigid tail-portion mounted on and extending rearwardly from said rear, spar, the upper portions of said flexible body-portion and said rigid tail-portion being rigidly united while the lower portions of the same are united for limited longitudinal sliding movement of said tailportion relativeto said body-portion.

f. A variable camber rib for aeroplane wings having front and rear spars, comprising a flexible body-portion consisting of upper and lower flexible longitudinal mem bers having their forward ends fixed to said front spar, a series of compression links intermediate said members and pivotally connected with the latter, means for limiting the flexing movements of said members, and a ri id tail-portion having a slidable and oscillatable relation to said rear spar, said rigid tail-portion having the upper portion of its forward end fixed to the rear end of said upper flexible member and the lower portion of its forward end slidably related to the rear end of said lower flexible menu 5. A variable camber rib for aeroplane wings having front and rear spars, comprising a flexible body portion consisting of upper and lower flexible longitudinal members having their forward ends fixed to sald front spar, a series of compression llnlcs spaced longitudinally intermediate said members, means for pivoting the ends of.

said compression links respectively to said upper and lower flexible members, flexible diagonal bracingstraps mterconnected between said upper and lower flexible memper and lower flexible longitudinal members having their forward ends fixed to said front spar, a series of compression links spaced longitudinally intermediate said members, means for pivoting the endsof said compression links respectively to said upper and lower flexible members. a series of flexible diagonal bracing straps interconnccted between said upper and lower flexible members to limit the flexing thereof when desired change of shape from streamline to lifting form is attained, a second series of flexible diagonal straps interconnected between said upper and lower flexible members to limit the flexing thereof when desired change of shape from lifting to streamline form is attained, and a rigid tail-portionhaving a slidable and oscillatable relation to said rear spar associated with said upper and lower flexible members and operated by the flexing movements thereof.

7 A variable camber rib for aeroplane wings having front and rear spars, comprising a flexible body portion consisting of upper and lower flexible longitudinal members having their forward ends fixed to said front spar, a series of compression links spaced longitudinally intermediate said members, means for pivoting the ends of said compression links respectively to said upper and lower flexible members, a series of flexible diagonal bracing straps interconnected between said upper and lower flexible members to limit the flexing thereof when desired change of shape from streamline to lifting form is attained, a second series of flexible diagonal straps interconnected" between said upper and lower flexible members to limit the flexing thereof when desired change of shape from lifting to streamline form is attained, and a rigid tail-portion having a slidable and oscillatable relation to said rear spar, said tail-portion hav-- ing the upper portion of its forward end fixed to the rear end of said upper flexible member and the lower portion of its forward end slidably related to the rear end of said lower flexible member.

8. A variable camber rib for aeroplane wings having front and rear spars, comprising a flexible body-portion consisting of upper and lower flexible longitudinal members having their forward ends fixed to said front spar, a series of compression links spaced longitudinally intermediate said members, means for pii oting the ends of said compression links respectively to said upper and lower flexible members, a series of flexible diagonal bracing straps interconnected between said upper and lower flexible members to'limit the flexing thereof when desired change of shape from streamline to lifting form is attained, a second series of flexible diagonal straps interconnected between said upper and lower flexible members to limit the flexing thereof when desired change ofshape from lifting to streamline form is attained, a rigid tail-portion having a slidable and oscillatable relation to said rear spar, said tail-portion having the upper portion of its forward end fixed to the rear end of said upper flexible member and the lower portion of its forward end slidably related to the rear end of said lowerflexiblc member and spring v means arranged between said rear spar and I thereof, and arigid tail-portion having a slidable and oscillatable relation to said rear spar, said tail-portion having the upper portion of its forward end fixed to the rear end of said upper flexible member and the lower portion of its forward end slidably related to the rear end of said lower flexible member, and spring means arranged between said rear spar and said tail-portion to supplement thetension of said upper and lower flexible members.

10. A variable camber rib for aeroplanewings having front and rear spars, comprising a flexible body portion consisting of upper and lower flexible longitudinal members having their forward ends fixed to said front spar, a series of compression links intermediate said members and pivotally connected with the latter, means for limiting the flexing movements of saidm m' bers, a rigid tail-portion having a slidable and oscillatable relation to said rear spar, said rigid tail-portion having the upper portion of its forward end fixed to the rear end of said upper flexible member and the lower portion of its forward end slidably related to the rear end 10f said lower flexible member, and spring means arranged between said rear spar and said tail-portion to supplement the tension of said upper and lower flexible members.

11. A vari ble camber rib for aeroplane wings having front and rear spars, cqmprising a exible body-portion consisting of upper and lower flexible longitudinal members having their forward ends fixed i Sai r n p a S r es. o empr sbn links spaced longitudinally intermed ate sai m ber means for p t n the nd of said compression respectively to S upp a d ow flex b e memb rs, a series of flexible diagonal bracing straps interconnected betweensaid upper and lower x l memb r he limi the flexin thsrse when d r d ange of hare frmii str ss: line to lifting form s atta ne a s wed series of le di gqnal strap 'i t rcennectedbetween said upper and lower flexi ble members to limit the flexing thereof ment the tension of said upper and lower 4 flexible members.

12. A variable camber rib for aeroplane w ngs having front and rear spars, comprising a flexible body-portion having its forward end fixed to said front spar, a rigid tail-portion having a slidable and oscillatable relation to said rear spar, said tailportion being connected with said flexible body portion whereby upward :flexing of the'latter produces a limited forward sliding movement upon anda downward swing from said rear spar of saidtail-portion, and sprlng means arranged between said rear Spar and said tail-portion tosupplemenjt the flexed tension of said flexible body portion.

,1 3,'A variable camber rib for aeroplane wings hav ng front and rear spars, comprising a flexible body-portion 'between said front and rear spars, a rigid tail-portion mounted on and extending rearwardly from d e par, he uppe po ns of said flexib b dy-P r ion nd d r g taih Po tion being rigidly united while the lower portions of the same are united for limited qns t d n' l l d g movement, of sa t h p en re i t sai b dy-P r i n, and spring means arranged between saidrear spar and said tail-portion to supplement the exed te ion of a fle ible bd y-po tim l4. Avariable'camber rib for aeroplane wings aving ront nd ar p r ompr ing a flexible body-portion consisting of an .upper flexible member of shallow channeled te l and a lower flexibl member f he llow channeled steel, said members having their forward ends secured to said front' spar, an intermediate truss-like strncture in articulated,intereeonnection with said upper and ower x e membe s, nd a g d a lportion having a slidable and oscillatable re- Iatim to s i rea s Jar, aid tail-D ee having the upper portion of its forward end fixe e r n f said ppe fl xi member and the lower portion of its forard en s idahly r ted to h ea nd Of said ower flexib e m mber-- 15. A variable camber rib for aeroplane wings having. front and rear spars, compr sing a ex ble b yo ies ens ng o a u er flexib e membe f s llew n led s eel and a brief fl xi le m m r o S lqw channeled s l, said mb rs. vin as: irward. ends e u a a d ron spar. an interme e tr ss-l Structure in artifiillatqd interconnection with said upper lower flexible members, a rigid tail-portion having a slidable and oscillatable relation to said rear spar, said tail-portion having the upper portion of its forward end fixed to the rear end of said upper flexible member and the lower portion of its forward end slidably related to the rear end of said lower flexible member and spring means arranged between said rear spar and said tail-portion to supplement the tension of said upper and lower flexible members.

16. A variable camber rib for aeroplane .wings having front and rear spars, comprismg a flexible body-port1on consisting of an ward 'end slidably related to the rear end of.

said lower flexible member,

17. A variable camber rib for aeroplane wings having front and rear spars, comprising a flexible body-portion consisting of an upper flexible member of shallow channeled steel and a lower flexible member of shallow channeled steel, said members having their forward ends secured to said front spar, a series of compression links extending between and pivoted by their ends to said upper and lower flexible members, means for limiting the flexing movements of said flexible members, a rigid tail-portion having the upper portion of its forward end fixed to the rear end of said upper flexible member and the lower portion of its forward end slidably related to the rear end of said lower flexible member spring and means arranged between said rear spar and said tail-portion to supplement the tension of said upper and lower flexible members.

184A variable camber rib for aeroplane wings having front and rear spars, comprismg .a pair of vertically spaced longitudi- -nally extending flexible members having their forward ends fixed to said front spar, and intermediate truss-like structure -in ar ticulated interconnection with said flexible members, a rigid tail-portion having a slid able and oscillatable relation to said rear spar, said tail-portion having the upper portion of its forward end fixed to the rear end of the uppermost flexible member and the lower portion of its forward end slid-ably related to the rear end of said lowermost flexible member.

19. A variable camber rib for aeroplane wings having front and rear spars. comprising-aa pair of vertically spaced longitudinally extending flexible members having their forward ends fixed to said front spar, and intermediate trnss-like structure in articulated interconnection with said flexible members, a rigid tail-portion having a slidable and oscillatable relation to said rear spar, said tail-portion having the upper portion of its forward end fixed to the rear end of the uppermost flexible member and the lower portion of its forward end slidablv related to the rear end of said lowermost flexible member and spring means arranged between said rear spar and said tail-portion to supplement the tension of said upper and lower flexible members.

In testimony. that I claim the invention set forth above I have hereunto set my hand this second day of July, A. D. 1919.

HUMPHRE l FRANU] S PARKER:

lid) 

